Technical Field
The present invention relates to an apparatus to create the uniform electric-field and magnetic-field distribution as zeroth-order resonance in a waveguide and a cavity and a leaky-wave waveguide antenna for high directivity radiation from 1 slot as a small structure.
Background Art
The rectangular waveguide is a transmission line guiding high frequency signals. In particular, it has excellent properties as a microwave transmission line with low loss, high quality-factor and high-power handling.
Meanwhile, a general waveguide has a distribution where the phase and size of the electric field and magnetic field of the basic and higher-order modes of transverse electric (TE) and transverse magnetic (TM) vary periodically like the standing wave in the waveguide and cavity. The electric field has an energy distribution alternating up and down with respect to the transmission direction, and the magnetic field has an energy distribution alternating to the left and right with respect to the transmission direction.
Therefore, in case of forming a microwave resonator by opening or shortening both the ends of the waveguide, there is a problem that the energy of the electric field and magnetic field change up and down or left to right, thereby failing to convey the equal power-density over the entire internal space of the cavity, which causes a microwave oven or RF heater not to have the desirable heat distribution.
Also, as for the existing slot-array travelling-wave or leaky-wave antenna used for radar detectors, etc., since a plurality of slits separated by half-wavelength intervals need to be formed in order to generate a beam for good directivity, and thus there is a problem that the size of the antenna gets bigger and therefore experiences more insertion loss.